21. Fig. 4.1 shows part of a fairground ride with a carriage on ralls.
3.9 m
30°
Fig. 4.1
The carriage of mass 500 kg is travelling towards a slope inclined at 30° to the horizontal.
The carriage has a kinetic energy of 25 kJ at the bottom of the slope. The carriage comes to
rest after travelling up the slope to a vertical height of 3.9 m.
a) Show that the potential energy gained by the carriage is 19 kJ.
g=9.8

b) Calculate the work done against the resistive forces as the carriage moves up the slope.
work done = ...​